Temperature control system and methods for operating same

ABSTRACT

A method for operating a temperature control system having a cooling system and ventilation system to vent outside air within a structure is disclosed. The method includes monitoring an interior temperature of the structure, monitoring an exterior temperature of ambient air outside of the structure, defining a first time range and a second time range, associating one or more operating parameters of the temperature control system with the first time range, associating one or more operating parameters of the temperature control system with the second time range, monitoring operational time and operational load of the cooling system for the first time range, predicting a space temperature and an outdoor air temperature for a subsequent time period, and controlling the ventilation subsystem during the second time range based upon the monitored operational time and operational load of the cooling subsystem for the first time range, the monitored interior and exterior temperatures, the predicted space temperature, the predicted outdoor air temperature, and the one or more operating parameters of the cooling subsystem associated with the second time range.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation-in-part of U.S. patent applicationSer. No. 14/830,807, filed Aug. 20, 2015, which claims the benefit ofU.S. Provisional Application Ser. No. 62/041,701, filed Aug. 26, 2014,all of which are hereby incorporated herein by reference for allpurposes.

TECHNICAL FIELD

This disclosure relates to temperature control of buildings and otherstructures, and more particularly to predictive systems and methods forheating, cooling and/or ventilating buildings and other structures.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may not constitute prior art.

Temperature control systems such as heating, ventilation, and airconditioning (HVAC) systems of structures, are operable to condition theinterior air of the structure, i.e., to selectively heat and cool theinterior air of the structure. The HVAC system includes mechanicalsystems for heating and cooling air that is delivered into the interiorof the structure via ductwork, to selectively heat or cool the interiorair.

Many HVAC systems have electronically controlled exterior air dampers,which are capable (when used in conjunction with the blower of the HVACsystem) of circulating “fresh” exterior air into the structure. Inaddition to HVAC systems having mechanical means (cooling systems, oftenutilizing compressor(s), condenser fans, blower motors, etc.) tocondition the space of the structure, many HVAC systems have the meansto utilize cool exterior air to condition the space, via an exterior airdamper (also referred to as an “economizer”).

Many structures have electronically controlled exhaust systems, whichare capable of exhausting air from the structure. Often, a structure'sexhaust system(s) draws air from near the roof of the structure, andexhausts that air to the outside of the structure.

The operation of the mechanical systems, e.g., cooling, heating, and/orventilation systems, consumes energy, adds wear and tear to theequipment, and increases the failure rate of that equipment, which maybe financially costly. As such, it is desirable to condition theinterior air of the structure to desired temperatures by utilizingpredictive data.

SUMMARY

A method for operating a temperature control system having a coolingsystem and ventilation system to vent outside air within a structure isdisclosed. The method includes monitoring an interior temperature of thestructure, monitoring an exterior temperature of ambient air outside ofthe structure, defining a first time range and a second time range,associating one or more operating parameters of the temperature controlsystem with the first time range, associating one or more operatingparameters of the temperature control system with the second time range,monitoring operational time and operational load of the cooling systemfor the first time range, predicting a space temperature and an outdoorair temperature for a subsequent time period, and controlling theventilation subsystem during the second time range based upon themonitored operational time and operational load of the cooling subsystemfor the first time range, the monitored interior and exteriortemperatures, the predicted space temperature, the predicted outdoor airtemperature, and the one or more operating parameters of the coolingsubsystem associated with the second time range.

This summary is provided merely to introduce certain concepts and not toidentify key or essential features of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments will now be described, by way of example, withreference to the accompanying drawings, in which:

FIG. 1 schematically shows an exemplary HVAC system, in accordance withthe present disclosure;

FIG. 2 schematically shows an exemplary HVAC controller, in accordancewith the present disclosure;

FIG. 3 is a control scheme for operating the exemplary HVAC system, inaccordance with the present disclosure;

FIG. 4 is a control scheme for operating the exemplary HVAC system usingenthalpy values, in accordance with the present disclosure;

FIGS. 5 and 6 graphically illustrate exemplary occupied operational timeranges and load output for a cooling system and a heating system forcalculation of a cooling potential of a building or other structure, inaccordance with the present disclosure;

FIG. 7 graphically shows operation of the HVAC system for ventingoutside air into a structure with respect to indoor temperature, inaccordance with the present disclosure;

FIGS. 8A and 8B are control schemes for operating the temperaturecontrol system, in accordance with the present disclosure;

FIG. 9 graphically illustrates a heat transfer metric with respect totemperature, in accordance with the present disclosure; and

FIGS. 10A and 10B graphically illustrates exemplary operating metrics ofthe temperature control system, in accordance with the presentdisclosure.

DETAILED DESCRIPTION

Throughout the specification and claims, the following terms take atleast the meanings explicitly associated herein, unless the contextdictates otherwise. The meanings identified below do not necessarilylimit the terms, but merely provide illustrative examples for the terms.The meaning of “a,” “an,” and “the” includes plural reference, and themeaning of “in” includes “in” and “on.” The phrase “in one embodiment,”as used herein does not necessarily refer to the same embodiment,although it may. Similarly, the phrase “in some embodiments,” as usedherein, when used multiple times, does not necessarily refer to the sameembodiments, although it may. As used herein, the term “or” is aninclusive “or” operator, and is equivalent to the term “and/or,” unlessthe context clearly dictates otherwise. The term “based upon” is notexclusive and allows for being based upon additional factors notdescribed, unless the context clearly dictates otherwise. The word“exemplary” is used herein to mean “serving as an example, instance, orillustration.” Any embodiment described herein as “exemplary” is notnecessarily to be construed as preferred or advantageous over otherembodiments. As used herein the terms building and structure may be usedinterchangeably. Upon a careful reading of the teachings herein, oneskilled in the art may readily apply the teachings to any number ofbuilding and structure types falling within the spirit of thisdisclosure.

Various embodiments of the present invention will be described in detailwith reference to the drawings, where like reference numerals representlike parts and assemblies throughout the several views. Reference tovarious embodiments does not limit the scope of the invention, which islimited only by the scope of the claims attached hereto. Additionally,any examples set forth in this specification are not intended to belimiting and merely set forth some of the many possible embodiments forthe claimed invention.

Referring now to the drawings, wherein the depictions are for thepurpose of illustrating certain exemplary embodiments only and not forthe purpose of limiting the same, FIG. 1 schematically shows anexemplary temperature control system 10 that may help implement themethodologies of the present disclosure. The system 10 may includevarious HVAC equipment components 8 configured to condition the interiorair of the structure, i.e., to selectively heat and cool the interiorair of the structure. The system 10 includes a controller 6 forcontrolling the HVAC equipment components 8. In various embodiments, thesystem 10 may include a server 5, a network 4 and/or a mobile device 2.The methods and devices of the present disclosure may be practiced withthe HVAC system 10 and/or as part of HVAC system 10.

The server 5 may be directly communicatively connected to the controller6 and the mobile device 2 or communicatively connected via the network4. The server 5 may be: various embodiments of a computer includinghigh-speed microcomputers, minicomputers, mainframes, and/or datastorage devices. The server 5 preferably executes database functionsincluding storing and maintaining a database and processes requests fromthe controller 6 and/or mobile device 2 to extract data from, or update,a database as described herein below. The server 5 may additionallyprovide processing functions for the mobile device 2 and the controller6 as will become apparent to those skilled in the art upon a carefulreading of the teachings herein.

As shown in FIG. 1, the HVAC controller 6 may be directlycommunicatively connected to one or more of the HVAC equipmentcomponents 8 including one or more sensors 31, 32, 33, and/or 34. In oneembodiment, the controller 6 is wirelessly connected to the one or moreHVAC equipment components 8 via the network 4. In embodiments utilizinga mobile device 2, the mobile device 2 may be physically or wirelesslyconnected to the network 4 and/or the controller 6 during selectedperiods of operation without departing from the teachings herein.Components of the system 10 are shown in FIG. 1 as single elements. Suchillustration is for ease of description and it should be recognized thatthe system 10 may include multiple additional components in variousembodiments without departing from the teachings herein. For example, invarious embodiments the controller 6 may be incorporated into the server5.

The exemplary HVAC system 10 shown in FIG. 1 includes an HVAC controller6, which may be or may include a thermostat or a hydronic heat transfersystem control in some embodiments. The HVAC controller 6 may beconfigured to communicatively interact with and control variouscomponents of the HVAC components 8. As shown in FIG. 1, the HVACcontroller 6 may be directly connected to the HVAC components 8 orconnected via a network 4 which may be a locally based network or awider network such as the Internet. In various embodiments, the mobiledevice 2 is communicatively connected to the controller 6 so that a usermay control the HVAC components 8 using the mobile device 2 via thecontroller 6.

The HVAC components 8 may include a heating system 12, a cooling system14, a ventilation system 16 including a fan, i.e., a blower, ahumidification system 18 and/or any other HVAC components or systems, asdesired such as an outside air damper 22 or intake damper 23. In variousembodiments, HVAC components include auxiliary heating and coolingequipment. Exhaust fans 37 and supply air fans 16, removing air from thestructure, and moving air into the structure, respectively, may also beused in various embodiments. The HVAC components 8 primarily function asa forced air system although auxiliary HVAC components may be used inconjunction to supplement conditioning of the environment within thebuilding. For example, auxiliary heat may be provided by electricalresistive heaters, hot water radiant heat, boilers, and/or electric baseboard heaters in various embodiments.

As illustrated in exemplary FIG. 1, the heating system 12 and thecooling system 14 are combined in a forced air system; however, it iscontemplated herein that the heating and cooling systems 12 and 14 maybe separated. For example, in residential and/or light commercialapplications, in various embodiments, a heat pump system may be utilizedseparate from an air conditioning cooling system 14.

In various embodiments the HVAC components 8 include any number ofintake and outtake dampers. In the illustrated embodiment a filter 21, afirst damper 22, and a second damper 23 are utilized consistent with theteachings herein. The damper 22 may be in communication with outside airand the fan 16 is in communication with one or more of the dampers 22and 23 within a ducting 24, for example. The dampers 22 and 23 may beselectively actuatable as a group or individually in variousembodiments.

The HVAC components 8 may include cooling equipment, which may includemore than one unit and/or more than one stage of cooling. The HVACcomponents 8 are selectively in gaseous communication with exteriorambient air and including operability to intake and/or vent exteriorambient air. In various embodiments the ventilation equipment mayprovide different levels of air movement as described herein below. TheHVAC components 8 may include other units such as a humidifier unit, adehumidifier unit, a UV filter unit and/or any other suitable HVAC unitand/or equipment as desired.

The HVAC components 8 may include one or more sensors, such as anexterior ambient air temperature sensor 31, an exterior humidity sensor32, a return temperature sensor 33, and/or a smoke detector 34. Thesensors 31, 32, 33, and 34 may be directly or indirectly communicativelyconnected to the controller 6. The exterior ambient temperature sensor31 is configured to measure a temperature of the outside air and, forexample, may be mounted to an exterior of the building, or factoryinstalled as part of the HVAC components 8. The exterior humidity sensor32 may also be mounted external to ducting of the HVAC components 8 orfactory installed as part of the HVAC components 8. An interiortemperature sensor 35 measures a temperature of the interior air of thebuilding. The sensor 35 may be internal to the controller 6 or external.Optionally, an interior humidity sensor 36 measures the humidity of theinterior air of the structure. The sensor 36 may be internal to thecontroller 6 or external. In one embodiment, the controller 6 may obtainoutside, i.e., exterior air temperature and/or humidity conditionsthrough an online weather service or may be in communication with abuilding automation system having equivalent measuring functionality. Inone embodiment, predicted weather conditions may be utilized by thecontroller 6. In various embodiments, the interior and exterior humiditysensors 36 and 32 are optional. In various embodiments, sensors 33 and34 are optional.

The network 4 may be any suitable series of points or nodesinterconnected by communication paths. The network 4 may beinterconnected with other networks and contain sub network(s) such as,for example, a publicly accessible distributed network like the Internetor other telecommunications networks (e.g., intranets, virtual nets,overlay networks and the like). The network 4 may facilitate theexchange of data between and among the HVAC components 8, the HVACcontroller 6, and the sensors 31, 32, 33, 34, 35 and 36; although invarious embodiments the HVAC controller 6 may be directly connected tothe HVAC components 8 and/or the sensors 31, 32, 33, 34, 35 and 36.

In various embodiments, the mobile device 2 may include one or moreapplications that the user may operate. Operation may includedownloading, installing, turning on, unlocking, activating, or otherwiseusing the application in conjunction with the controller 6. Theapplication may comprise at least one of an algorithm, software,computer code, executable instruction sets and/or the like, for example,mobile application software. In the alternative, the application may beutilized remotely through a website accessible through the world wideweb.

FIG. 2 shows the exemplary HVAC controller 6. The controller 6 includesa central processing unit (CPU) 50, random access memory (RAM) 52,input/output circuitry 54 for connecting peripheral devices such as astorage medium 56 to a system bus 60, a display adapter 58 forconnecting the system bus 60 to a display device, a user interfaceadapter 62 for connecting user input devices such as various dialsbuttons and/or keypads, to the system bus 60, and a communicationadapter 64 for connecting the controller 6 to the network 4. The memory52 and storage medium 56 may be used to store any appropriateinformation such as HVAC control routines or code, historicalperformance data, HVAC system and/or HVAC controller parameters, one ormore programmable schedules for changing HVAC system parameters overtime, etc.

The central processing unit 50 is preferably one or more general-purposemicroprocessor or central processing unit(s) and has a set of controlalgorithms, comprising resident program instructions and calibrationsstored in the memory 52 and executed to provide the desired functions.In one embodiment, an application program interface (API) is preferablyexecuted by the operating system for computer applications to makerequests of the operating system or other computer applications. Thedescription of the central processing unit 50 is meant to beillustrative, and not restrictive to the disclosure, and those skilledin the art will appreciate that the disclosure may also be implementedon platforms and operating systems other than those mentioned.

The HVAC controller 6 may include any number of suitable componentsrelated to effecting control of the HVAC system 10. For example, HVACcontroller 6 may include a user interface 68 which may be graphical. Theuser interface 68 may include one or more displays, switches, and/orbuttons that a user may actuate or otherwise control. In one embodiment,a touchscreen display may be provided to display the user interface 68and provide interaction therewith.

In one embodiment, one or more of a cooling device, heating equipmentand/or ventilation equipment may be distinct systems controlled, eitherdirectly or indirectly, by the HVAC controller 6. In some embodiments,it is contemplated that the HVAC controller 6 may separately controleach component 8. HVAC system parameters may include set points forheating, cooling, humidity, etc., modes for ventilation equipment, fansettings, and the like and as further described below.

The HVAC controller 6 may include one or more internal sensors 65, suchas a temperature sensor and/or a humidity sensor. The internal sensors65 may be in addition to the sensors 35 and 36 and may be used forsupplemental or redundancy purposes, as exemplary. The HVAC controller 6may include one or more outputs configured to issue operation commandsto the HVAC components 8. It is contemplated herein that the HVACcontroller 6 may be configured to execute any method of the presentdisclosure. The HVAC controller 6 may be communicatively connected toone or more sensors connected external to a building structure andexternal to a housing of the controller 6. The connection may be viawire or via a wireless embodiment of the network 4.

In various embodiments, the HVAC controller 6 may maintain in its memoryan operating schedule that may be used to control the HVAC system basedupon time and/or day. The schedule may, for example, be a dailyprogrammable schedule or any other schedule. In some cases, the schedulemay have a number of days and one or more time periods for each of atleast some of the days. In some instances, the nominal schedule mayinclude an “occupied”, an “unoccupied”, and a “stand-by” time period foreach of the days of a week. The schedule may have at least one set pointassociated with each of the one or more time periods. The schedule maybe maintained in the memory 52, and may be modified by an end user invarious embodiments.

FIG. 3 shows a control scheme 100 for operating the controller 6 and theHVAC components 8. Although the control scheme 100 is shown as discreteelements, such an illustration is for ease of description and it shouldbe recognized that the functions performed by the control scheme 100 maybe combined in one or more devices, e.g., implemented in software,hardware, and/or application-specific integrated circuitry (ASIC) andexecuted, in some cases, concurrently or in parallel. For example,monitoring of the various sensors may be executed concurrent with anynumber of execution steps.

The control scheme 100 is directed at operating efficiencies that can begained from utilizing exterior ambient conditions to ventilate outsideair into the structure and/or condition the interior environment. Forexample, during warm summer months, the coldest part of the day istypically in the early morning, such as between 4:00 am and 6:00 am. Asset forth further below, during this early morning time, the controller6 instructs one or more of the HVAC components 8 to operate to effectthe intake of cool exterior air (and either passively or activelyexhaust warm interior air) based upon exterior air conditions, interiorair conditions, the usage of the HVAC components 8 during the previousday, and current settings of the HVAC components 8. In other words,based upon these variables, the controller 6 may instruct the HVACcomponents 8 to intake cool exterior air, and optionally to exhaust warminterior air to decrease the temperature of the interior air of thestructure to a temperature between the occupied heating set point andthe occupied cooling set point of the HVAC components 8, as shown inFIG. 7.

To capitalize on preferential exterior ambient conditions and achievegreater operating efficiencies, the control scheme 100 is configured, inone exemplary implementation, to operate one or more of the HVACcomponents 8 using the controller 6 to condition the interiorenvironment. As FIG. 3 shows, the control scheme 100 is initiated atstep 102 whereby the controller 6 operates the HVAC components 8 basedupon a user's predefined or default operating parameters, and theresults of a prior iteration of the control scheme 100. In the exemplarycase of cooling the interior air of a building, the control scheme 100operates during cool mornings to proactively ventilate the building withcool exterior air based upon the operation of the HVAC components 8during a previous period, e.g., during the previous day.

In one embodiment, the HVAC components 8 may transition between anoccupied state and an unoccupied state. In one embodiment, the controlscheme 100 is operated only at a predetermined time range. Whileoperating in an occupied state, the controller 6 typically operates tomaintain interior air conditions at desired levels, for example, levelsdirected at maintaining comfortable conditions for occupants, e.g., auser-supplied set point. In one embodiment, while in the predeterminedtime range, the controller 6 executes the control scheme 100 to maintaininterior air conditions at a second set of preferential conditions,which may be directed at a different set of objectives, e.g., energyconservation, equipment wear reduction, and/or improvement of indoor airquality.

In one embodiment, operation of one or more of the HVAC components 8 maybe based upon operation that occurred during the previous period. Theprevious period may be, for example the previous day, i.e., the previous24 hours. Alternatively, the previous period may be, for example, theprevious day less any time duration during which the process 100operated. For example, if the process 100 operated for two hours duringthe previous day (for example, from 4:00 am to 6:00 am), the previousperiod may be 22 hours (i.e., 24 hours minus 2 hours).

At step 104, the controller 6 may execute the control scheme 100 duringa predefined operating time range. The controller 6 may then deactivatethe control scheme 100 after or outside of the predefined operating timerange. The operating time may be between 4:00 am and 6:00 am, forexample. In one embodiment, the operating time range may beuser-defined. Alternatively, the operating time range may initiate atany suitable predefined time and may last for any suitable predefinedduration. In one embodiment, operating time may be defined based uponoccurrence of an event. In one embodiment, operating time may begin atany suitable predefined time, and not terminate until block 116 or block120 of FIG. 3 is “no”. In one embodiment, operating time may be definedbased upon historical trending of the coolest part of the day. Asexemplary, a photocell could be utilized to estimate a time of dawn, andthen, in turn, apply that time to the next day's predetermined start andstop times of the operating range. In one embodiment, a start and stoptime of the control scheme 100 may be determined based upon monitoredexterior air temperature. For example, a time associated with a lowesttemperature reading may be set as the start time or a predetermined timeperiod before the monitored lowest temperature may be set as the starttime and a predefined duration after the start time may be calculatedfor the stop time.

At step 106, the control scheme 100 determines a cooling potential ofthe interior air based upon the previous period, e.g., the previous day.Determining the cooling potential includes determining the cooling usageof the HVAC components 8 from the previous period, e.g., the previousday. More specifically, determining the cooling potential includesadding the sum of the products of cooling load output and run time ofthe HVAC components 8 from the previous period, which may be calculatedusing the following equation:

cocrt_(—sum)=(co₁*crt₁)+(co₂*crt₂)+ . . . (co_(n)*crt_(n))

whereinco=cooling load output (as a factor of the total possible cooling loadoutput);crt=the cooling run time of the co (over the run time period of the co);n=the total number of cooling states in the (user defined) previousperiod; andcocrt_(—sum)=the sum of the products of the cooling load outputs (overthe time period) and the corresponding cooling run times (over the timeperiod).

To illustrate using example values, if in the previous period thecooling system 14 operated in cooling mode at 50% load output for aperiod of 30 minutes, and at 100% load output for a period of 180minutes, then

cocrt_(—sum)=(co₁*crt₁)+(co₂*crt₂)

cocrt_(—sum)=(0.5*30 minutes)+(1*180 minutes), which reduces to:cocrt_(—sum)=(15 minutes)+(180 minutes), which is reduced to:cocrt_(—sum)=195 minutes.

Determining the cooling potential includes determining the heating usageof the heating system 12 from the previous period, e.g., the previousday. More specifically determining the cooling potential includes addingthe sum of the products of heating load output and operating time of theheating system 12 from the previous period, which may be calculatedusing the following equation:

hohrt_(—sum)=(ho₁*hrt₁)+(ho₂*hrt₂)+ . . . (ho_(n)*hrt_(n))

whereho=heating load output (as a factor of the total possible heating loadoutput);hrt=heating run time of the ho (over the run time period of the ho,while ho is in a stable state);n=the total number of heating states in the user defined time periodbeing measured; andhohrt_(—sum)=the sum of the products of the heating load outputs (overthe time period) and the corresponding heating run times (over the timeperiod).

To illustrate using example values, if in the previous period theheating system 12 operated in heating mode at 50% load output for aperiod of 30 minutes, and at 100% load output for 180 minutes, then

hohrt_(—sum)=(ho₁*hrt₁)+(ho₂*hrt₂);

hohrt_(—sum)=(0.5*30 minutes)+(1*180 minutes);

hohrt_(—sum)=(15 minutes)+(180 minutes); and hohrt_(—sum)=195 minutes.

The cooling potential is calculated by subtracting the sum of theproduct of the heating load output and the run time (hohrt_(—sum)) fromthe sum of the cooling load output and run time (cocrt_(—sum)).Specifically, the controller 6 subtracts the hohrt_(—sum) from thecocrt_(—sum) to obtain the cooling potential (cp). For example, usingthe example values above:

If cp (cooling potential)=cocrt_(—sum)−hohrt_(—sum); If thehohrt_(—sum)=100 minutes;

and

If the cocrt_(—sum)=150 minutes; then cp=cocrt_(—sum)−hohrt_(—sum)

cp=150 minutes−100 minutes; and cp=50 minutes

FIGS. 5 and 6 graphically illustrate exemplary time ranges of exemplaryoperation of a cooling system and a heating system. FIG. 5 graphicallyshows a first sum of products of operational time and operational loadof the cooling system and a second sum of products calculation foroperational time and operational load of the heating system. Thecontroller may difference the second sum of products from the first sumof products. A positive result indicates cooling potential, while a zeroor negative result indicates no cooling potential.

FIG. 6 shows an alternative to a sum of products calculation. Forexemplary embodiments of cooling and heating equipment wherein coolingload output and heating load output are obtained as a function ofoperating load may be represented with respect to operating time. Todetermine a cooling potential the controller may execute a firstintegral calculation for an operational load of the cooling system as afunction of operational time over the first time range, execute a secondintegral calculation for an operational load of the heating system as afunction of operational time over the first time range and thendifference the second integral from the first integral. Similar toabove, a positive result indicates cooling potential, while a negativeresult indicates no cooling potential.

At step 108, the control scheme 100 subtracts a time bias quanta fromthe cooling potential (cp). The time bias may be defined or set by theuser. This time bias is subtracted from the cooling potential value toinhibit use of the control scheme 100 when only slightly more coolingthan heating was observed in the previous period. In such a situation,it is likely that having the equipment cool the structure in the earlymorning may actually cause the heating function to be energized prior tothe “heat of the day,” which may be around 3:00 pm. A user defined timebias may be adjusted or may be a default value, but as a default, thatvalue may be set to 60 minutes.

For example, based upon the example values above:

entc=cp−time_bias

whereintime_bias=time bias; andentc=enable control scheme 100 if positive value.

For example, if cp=50 minutes; and if time_bias is set to 60 minutes(which can be the default value); then entc=50 minutes−60 minutes; andentc=−10 minutes.

At step 110, the control scheme 100 determines whether the entc value ispositive or negative. If the entc value is zero or negative, the controlscheme 100 stops the process 100 until the next time period 130. Inother words, if the entc value is zero or negative (after being biasedby the user defined time bias), then conditions may, undesirably, causethe controller 6 to effectuate the heating system 12 during the upcomingperiod, before the heat of the day, if the control scheme 100 were toventilate the air in the building. Accordingly, when the entc 110 valueis negative, to avoid utilizing the heating system 12 after havingcooled the structure, the control scheme 100 is not operated to utilizethe exterior air damper 22, and/or fan 16 to intake outdoor air and/orthe exhaust fan(s) 37 to exhaust interior air thereby avoiding coolingthe structure undesirably and avoiding inefficient use of the heatingsystem 12 during the upcoming time period.

At step 112, the control scheme 100 measures indoor and outdoor airconditions. At step 114, the control scheme 100 adjusts an exterior airtemperature measurement using a user-defined or default temperaturebias. Factoring in a temperature bias will cause the controller 6 to beless likely to determine that the exterior air is suitable to use forcooling the structure. The greater the temperature bias, the less likelythe controller 6 will find the exterior air suitable. The temperaturebias is added to compensate for electrical consumption of the equipmentwhich operates during the control scheme 100 to cool the structure. Forexample, while running the fan(s) 16 alone consumes less electricitythan running a number of the other HVAC components 8, e.g., compressors,condenser fans, etc., there is still energy consumption used by simplyrunning the fan 16. The “break even” point for venting the exterior airis not when the exterior air temperature or enthalpy is slightly lessthan that of the interior air temperature or enthalpy, respectively, butis when the interior air temperature or enthalpy is significantlygreater than the exterior air temperature or enthalpy, respectively, sothat the cost to utilize the intake of exterior air and the exhaustingof indoor air (either passively or actively) for cooling is profitable,in terms of the cost per BTU of heat transfer (or electricityconsumption per BTU of heat transfer). Based on factors including, butnot limited to, indoor air humidity set points, fresh air intakeconsiderations, specific equipment characteristics, and the local costof electricity, the optimal temperature or enthalpy difference maychange. Enthalpy of the exterior air may be determined or estimatedusing exterior temperature and humidity measurements from the exteriortemperature sensor 31 and the exterior humidity sensor 32 using knowncalculation techniques and/or modeling processes.

At step 116, subsequent to determining that the entc value is positivethe control scheme 100 analyzes the exterior ambient air to determinewhether the exterior air is suitable. The determination of whether theexterior air is suitable may be based upon the use of industry standardenthalpy calculations, or temperature calculations, or some combinationof the two. Specifically, the interior air condition and exterior aircondition is measured. The suitability may be based upon interior andexterior air temperature and, optionally, humidity values, provided bythe sensors, such as interior temperature sensor 35, exteriortemperature sensor 31, interior humidity sensor 36, and exteriorhumidity sensor 32, network values, etc., or may simply utilize interiorand exterior air temperature sensors 35 and 31, respectively, networkvalues, etc. If the controller 6 determines that the exterior air is notsuitable for intake, then the control scheme is stopped at 130 and thecontroller 6 does not operate the damper(s) 22 and 23 and the fan 16 tointake exterior air, and optionally the exhaust fan(s) 37 to exhaustinterior air.

At step 118, subsequent to determining that the exterior air is suitablefor cooling (or economization), the controller 6 determines a night timecooling set point. The night time cooling set point is determined bysubtracting the occupied heating set point, e.g., a “heating” set pointon a conventional thermostat, from the occupied cooling set point, e.g.,a “cooling” set point on a conventional thermostat, multiplying thatvalue by a bias value (between 0 and 1, with a default of 0.67, forexample), and then subtracting that product from the occupied coolingset point. The bias value may be used, for example, to affect the degreeof pre-cooling within the building, with a larger biasing valueresulting in more pre-cooling and a smaller biasing value resulting inless pre-cooling. For example, the following equation applies:

ntcsp=ocsp−(ocsp−ohsp)*udbv

whereinntcsp=night time cooling set point; ocsp=occupied cooling set point;ohsp=occupied heating set point; and udbv=user defined bias value.

Example values are applied to this equation: If ocsp=70 F; If ohsp=65 F;and udbv=0.67; then ntcsp=ocsp−(ocsp−ohsp)*udbv: ntcsp=70 F−(70 F−65F)*0.67; ntcsp=70 F−5 F*0.67; ntcsp=70 F−3.35 F; and ntcsp=66.65 F.

As explained below, with respect to FIG. 4 and control scheme 200,alternatively to utilizing only temperature values to determine thentcsp, when humidity values are available, enthalpy values could beentered in place of temperature values to determine the ntcsp. In such acase, the value of the ntcsp could be expressed in terms of enthalpyrather than simple temperature. Likewise, alternatively to utilizingonly temperature values to determine the result of step 120, whenhumidity values are available, indoor air enthalpy and outdoor airenthalpy could be used rather than simple temperatures.

At step 120 the control scheme 100 has determined the ntcsp, it comparesthe ntcsp with the interior air temperature. If the interior airtemperature is less than or equal to the ntcsp, then the control scheme100 terminates all sequences 130.

At step 122, if the interior air temperature is greater than the ntcsp,then the control scheme 100 energizes, for example, a relay, triacoutput, network signal, etc., which will, at least, energize equipmentwhich causes cool outdoor air to enter the building, e.g., the fan 16,and open the exterior air damper 22 (also known as the fresh air damper22). The control scheme 100 may energize any connected exhaust equipmentsuch as the exhaust fan(s) 37, which may remove air from the building,to help facilitate economization of the primary heating, cooling, andventilation equipment. The relay, triac output, network signal, etc.will remain active until conditions change in blocks 110, 116, or 120.In one embodiment, the controller will terminate step 122 if thecontroller 6 is transitioned to an occupied state. In one embodiment,the controller 6 will terminate step 122 if a current time is outside ofthe predefined time range.

At various points in the control scheme 100, the controller 6 maytransition the one or more of the HVAC components 8 to a stoppedoperating state 130. The control scheme 100 may be configured totransition out of step 130 after a predefined duration of time or uponoccurrence of an event.

FIG. 4 shows a control scheme 200 for operating the controller 6 and theHVAC components 8 illustrating operation of the system 10 using enthalpyvalues determined from temperature and humidity measurements. Althoughthe control scheme 200 is shown as discrete elements, such anillustration is for ease of description and it should be recognized thatthe functions performed by the control scheme 200 may be combined in oneor more devices, e.g., implemented in software, hardware, and/orapplication-specific integrated circuitry (ASIC) and executed, in somecases, concurrently or in parallel. For example, monitoring of thevarious sensors may be executed concurrent with any number of executionsteps.

The control scheme 200 is directed at operating efficiencies that can begained from utilizing exterior ambient conditions to ventilate outsideair into the structure and/or condition the interior environment. Forexample, during warm summer months, the coldest part of the day istypically in the early morning, such as between 4:00 am and 6:00 am. Asset forth further below, during this early morning time, the controller6 instructs one or more of the HVAC components 8 to operate to effectthe intake of cool exterior air (and either passively or activelyexhaust warm interior air) based upon exterior air conditions, interiorair conditions, the usage of the HVAC components 8 during the previousday, and current settings of the HVAC components 8. In other words,based upon these variables, the controller 6 may instruct the HVACcomponents 8 to intake cool exterior air, and optionally to exhaust warminterior air to decrease the temperature of the interior air of thestructure to a temperature between the occupied heating set point andthe occupied cooling set point of the HVAC components 8, as shown inFIG. 7.

To capitalize on preferential exterior ambient conditions and achievegreater operating efficiencies, the control scheme 200 is configured, inone exemplary implementation, to operate one or more of the HVACcomponents 8 using the controller 6 to condition the interiorenvironment. As FIG. 4 shows, the control scheme 200 is initiated atstep 202 whereby the controller 6 operates the HVAC components 8 basedupon a user's predefined operating parameters, e.g., set points, and theresults of a prior iteration of the control scheme 200. In the exemplarycase of venting exterior air into an interior of the structure, thecontrol scheme 200 operates during cool mornings at predefined ordetermined times to proactively ventilate the building with coolexterior air based upon the operation of the HVAC components 8 during aprevious period, e.g., during the previous day.

At step 204, the controller 6 may execute the control scheme 200 duringa predefined operating time range, a predefined time duration having adetermined start time based upon prior measured exterior air conditionsand/or photocell measurements.

At step 206, the control scheme 200 determines a cooling potential ofthe interior air based upon the previous period, e.g., the previous day,similar to step 106 described herein above with respect to controlscheme 100.

At step 208, the control scheme 200 subtracts a time bias or buffervalue from the determined cooling potential (cp). This time bias issubtracted from the cooling potential value to prohibit use of thecontrol scheme 200 when only slightly more cooling than heating wasobserved in the previous period.

At step 210, the control scheme 200 determines whether the entc value ispositive or negative or zero. The entc value is the difference betweenthe cooling potential value and the time bias or buffer value. If theentc value is zero or negative, the control scheme 200 stops the process200 until the next time period by transitioning the control scheme 200to a stop state 230.

At step 212, the control scheme 200 measures interior and exterior airconditions including an exterior temperature and exterior humidity. Atstep 214, the control scheme 200 determines the exterior enthalpy usingthe monitored exterior air conditions including temperature andhumidity. Enthalpy of the exterior air may be determined or estimatedusing exterior temperature and humidity measurements from the exteriortemperature sensor 31 and the exterior humidity sensor 32 using knowncalculation techniques and/or modeling processes.

At step 215, the control scheme 200 adjusts the determined enthalpyvalue using a buffer value. Factoring in a buffer will cause thecontroller 6 to be less likely to determine that the exterior air issuitable to use for cooling the structure. The greater the buffer value,the less likely the controller 6 will find the exterior air suitable.The buffer value is added to compensate for electrical consumption ofthe equipment which operates during the control scheme 200 to cool thestructure. For example, while running the fan(s) 16 alone consumes lesselectricity than running a number of the other HVAC components 8, e.g.,compressors, condenser fans, etc. in combination with each other, thereis still energy consumption used by simply running the fan 16. The“break even” point for venting the exterior air is not when the exteriorair temperature or enthalpy is slightly less than that of the interiorair temperature or enthalpy, respectively, but is when the interior airtemperature or enthalpy is significantly greater than the exterior airtemperature or enthalpy, respectively, so that the cost to utilize theintake of exterior air and the exhausting of indoor air (eitherpassively or actively) for cooling is profitable, in terms of the costper BTU of heat transfer (or electricity consumption per BTU of heattransfer). Based on factors including, but not limited to, indoor airhumidity set points, fresh air intake considerations, specific equipmentcharacteristics, and the local cost of electricity, the optimaltemperature or enthalpy difference may change.

At step 216, subsequent to determining that the entc value is positivethe control scheme 200 analyzes the exterior ambient air to determinewhether the exterior air is suitable. The determination of whether theexterior air is suitable may be based upon the use of industry standardenthalpy calculations, or temperature calculations, or some combinationof the two. In one embodiment, the interior humidity value and exteriorhumidity values are compared. If the controller 6 determines that theexterior air is not suitable for intake, e.g., interior conditions arepreferable to exterior conditions, then the control scheme 200 isstopped at 230 and the controller 6 does not operate the damper(s) 22and 23 and the fan 16 to intake exterior air, and optionally the exhaustfan(s) 37 to exhaust interior air.

At step 218, subsequent to determining that the exterior air is suitablefor venting exterior air to the interior of the structure, thecontroller 6 determines a night time enthalpy cooling set pointsimilarly to the process described herein above with respect to controlscheme 100 only using enthalpy values and not exclusively temperaturevalues. The night time cooling set point 218 is determined bysubtracting the occupied enthalpy heating set point, from the occupiedenthalpy cooling set point, and then multiplying that value by a biasvalue (between 0 and 1, with a default of 0.67, for example), and thensubtracting that product from the occupied enthalpy cooling set point.For example, the following equation applies:

ntcsp=ocsp−(ocsp−ohsp)*udbv

whereinntcsp=night time cooling set point; ocsp=occupied enthalpy cooling setpoint;ohsp=occupied enthalpy heating set point; and udbv=user defined biasvalue.

At step 220 the control scheme 200 has determined the ntcsp, it comparesthe ntcsp with the interior enthalpy. If the interior air enthalpy isless than the ntcsp, then the control scheme 200 terminates allsequences by transitioning to block 230.

At step 222, if the interior air enthalpy is greater than the ntcsp,then the control scheme 200 energizes, for example, a relay, triacoutput, network signal, etc., which will, at least, energize equipmentwhich causes cool outdoor air to enter the building, e.g., the fan 16,and open the exterior air damper 22. The process may energize anyconnected exhaust equipment, which may remove air from the building, tohelp facilitate economization of the primary heating, cooling, andventilation equipment. The relay, triac output, network signal, etc.will remain active until conditions change in blocks 210, 216, or 220.In one embodiment, the controller will terminate step 222 if thecontroller 6 is transitioned to an occupied state. In one embodiment,the controller 6 will terminate step 222 if a current time is outside ofthe predefined time range.

At various points in the control scheme 200, the controller 6 maytransition the one or more of the HVAC components 8 to a stoppedoperating state 230. The control scheme 200 may be configured totransition out of step 230 after a predefined duration of time or uponoccurrence of an event.

FIG. 7 graphically shows operation of the HVAC system for ventingexterior air into a structure with respect to indoor temperature, whileoutdoor air is suitable for cooling 116. As FIG. 7 shows, specificcondition ranges related to the structure's interior and monitoredexterior temperature result in venting exterior air to the interior ofthe structure. In one embodiment, venting of the exterior air to theinside will occur when: (1) the time biased cooling potential ispositive; and (2) the indoor temperature is greater than a cooling setpoint associated with an unoccupied status of the structure, i.e.,(second time range). As illustrated in FIG. 7, the criteria for ventingof the exterior air to the inside is satisfied in zone 300.

As set forth above, in one embodiment the controller 6 may utilize athermostat of the HVAC components 8. For example, when the controller 6utilizes a conventional thermostat of the HVAC components 8, thefollowing is typical with most conventional thermostats: G terminal=fan16 on; Y1 terminal=cooling first stage; Y2 terminal=cooling secondstage; W1 terminal=heating first stage; W2 terminal=heating secondstage.

A capacitor may be set to charge when the Y1 terminal is activated, witha resistor inline with the capacitor, which acts as a regulator for thecurrent. The same capacitor could also be charged when the Y2 terminalis activated, which would also have an inline “regulator” resistor.Likewise, the heating terminals could also have a capacitor which ischarged via the W1 and W2 terminals, with “regulating” resistorsin-line. The charges of the two capacitors would be discharged via ashort, which is regulated by a (high value) resistor. At the initiationtime of the control scheme 100, e.g., 4:00 am, the total charges of eachof the two capacitors could be compared via an integrated circuit (IC)to determine the cooling potential (as set forth above) for the upcomingtime period. The time bias could be incorporated by adding apotentiometer to the circuit. When used in this configuration, somelevel of circuit integration could be added. For example, a time clockof the thermostat may be incorporated into the process. Similarly, theoccupied set points (or at least the lowest cooling set point) may beincorporated into the process.

In one embodiment, interior humidity and exterior humidity sensors areoptional, and a provision may be made to utilize both or only one typeof humidity sensor. In one exemplary application using only an exteriorhumidity sensor, the system 10 utilizes a default, predefined humidityreading as a reference marker to compare measurements from the exteriorhumidity sensor. For example, the system 10 may be configured to assumethat the interior humidity is at a first predefined level under a firstset of criteria, e.g., a reading from the exterior humidity sensor afterrunning the control scheme 100 for at least a first time period. Anotherexample, may assume that the interior humidity is simply at a predefinedlevel. During operation, the system 10 could compare the assumedhumidity value and the measured value until the exterior humidity levelsexceed 50% relative humidity, at which point the assumed interiorhumidity level would stay at 50%, while the actual relative humidityvalue for the exterior humidity levels would be reflected in thesystem's 10 calculations. In one embodiment, the control scheme 100 maystop if the exterior humidity is above and/or below a predeterminedthreshold.

On thermostat embodiments having a switch to select “cool” (only) or“heat” (only), there could be a calculated or user-defined ntcsp (seeabove). The calculated ntcsp could use a user defined temperature offsetvalue which may be set via programming the thermostat, or may simply usea default value of a certain number of degrees less than the lowestcooling set point on the thermostat.

FIG. 8A shows a block diagram illustrating an exemplary process 400 forcontrolling the system 10 based upon a calculated anticipated heatenergy transfer metric. Although FIG. 8A may show a specific order ofmethod steps, the order of the steps may differ from what is depicted.Unless specifically stated, the methods or steps shown in the flowchartsand described in the accompanying text are not constrained to aparticular order or sequence. In various embodiments, some of the stepsthereof can occur or be performed concurrently or with partialconcurrence and not all the steps have to be performed in a givenimplementation depending on the requirements of such implementation.Further, the order or sequence of any process or method steps may bevaried or re-sequenced according to alternative embodiments. Othersubstitutions, modifications, changes, and omissions may be made in thedesign, operating conditions and arrangement of the exemplaryembodiments without departing from the scope of the present disclosure.All such variations are within the scope of the disclosure.

At step 412 of the process 400, operating of the system 10 may includedetermining a fixed or minimum outdoor air damper position (FMOADP)using any one of the following equations:

FMOADP=(RAT−MAT)/(RAT−ODAT)

FMOADP=(MAT−RAT)/(ODAT−RAT)

FMOADP=1−((ODAT−MAT)/(ODAT−RAT))

FMOADP=1−((MAT−ODAT)/(RAT−ODAT))

whereODAT represents an outdoor air temperature which can be measured usingsensor 31, andRAT represents a return air temperature, which may be measured fromsensor 33, andMAT represents a mixed air temperature measured from sensor 39.

For example, if MAT=55° F., ODAT=50° F., and RAT=70° F., thenFMOADP=(70° F.−55° F.)/(70° F.−50° F.), which equals a value of 0.75,meaning that the outdoor air damper 22 is open 75%, where a ‘1’ value isdefined as completely open and a ‘0’ value is defined as closed.

In various embodiments, a discharge air temperature may be utilized todetermine FMOADP instead of the MAT variable as one skilled in the artwill recognize upon a careful reading of the teachings herein.

In various embodiments, the FMOADP could be calculated and trended(based on time or time in different states/values) for use later. Forexample, specific calculations of FMOADP at noon and at 2 pm, may betrended to determine position at 1 pm or 3 pm. In one embodiment, theFMOADP may be used in calculating the energy (or heat) added to, orremoved from the structure via the “fresh air intake”, or intake ofoutdoor air.

Additionally, heat transfer due to FMOADP and ventilation status (VS)may be calculated when considering temperatures. In various embodiments,depending on operating parameters of the system 10, historical heattransfer rates due to the intake of outdoor air may be used to predictthe heat transfer going forward. For example, the heat transferredduring the last same day of the previous week could be used to determineanother day's anticipated value, or may begin as the average heattransferred the last same day of the week and month for the first year,and/or then in later years, the average heat transferred on the same dayof the week and month in preceding years. In one exemplary application,a church might have nominal load demand on every day of the week exceptSunday. Basing the next day's predicted cooling potential based on thelast Sunday's actual load demand, or on the same Sunday from theprevious year's load demand may be beneficial instead of using the priorday's load demand.

In one embodiment, if multiple systems with different maximum volumetricflow rates are used, then a “VS constant” can be multiplied by eachindividual climate control equipment's value for VS, such that the valueof VS for each individual climate control equipment shall be inproportion to its volumetric flow rate in relation to all other climatecontrol equipment. For example: If two pieces of climate controlequipment are used, one capable of moving 4,000 CFM (unit #1), andanother capable of moving 8,000 CFM (unit #2), then the VS constant forunit #1 would be 0.5, and the VS constant for unit #2 would be 1.

At step 414 of the process 400, a numeric value for the variablerepresenting the heat transfer due to bringing outdoor air into andexpelling indoor air out of a structure may be determined, iterativelyat predetermined sampling intervals, e.g., at a time interval asfollows, while understandably similar calculations could be made byreplacing the temperature variables for enthalpy variables and modifyingthe equations slightly:

FMOADP_heat=VS*(ODAT−RAT)*FMOADP

whereFMOADP_heat=the heat transfer metric due to bringing outdoor air intoand expelling indoor air out of a structure,ODAT represents an outdoor air temperature,FMOADP represents a fixed or minimum outdoor air damper position,RAT represents a return air temperature or exhaust air temperature, andVS represents an operating status of the ventilation system 16 (e.g.,0=off, 1=on 100%, 0.5=50% output, etc.).

For example: If ODAT=60° F., FMOADP=0.1 (i.e., 10%), RAT=70° F., VS=1(on), then FMOADP_heat=1*(60° F.−70° F.)*0.1, which reduces to −1° F.

At step 416, the system 10 may determine FMOADP_Heat_sum.FMOADP_Heat_sum represents a heat transferred (based on the FMOADP_heatmetric), resulting from venting outdoor air into, and indoor air out of,the building structure for the entire period being measured (e.g., awhole day, 22 hours, one week, etc.). In exemplary applications havingmultiple climate control equipment (i.e. air conditioners, exhaust fans,etc.) within a building structure or zone, the FMOADP_Heat_sum can besummed with the FMOADP_Heat_sum of the other networked and/or controlledsystems, however, the FMOADP_heat calculation of each individual unitwould likely need to have a “VS constant” (as described above) appliedto the FMOADP_heat value for each individual unit. FMOADP_Heat_sum couldbe calculated as follows:

FMOADP_Heat_sum≈Σ_(i=1) ^(z) x _(i) t _(i)

wherex represents FMOADP_heat,t_(i) represents a predetermined time interval,FMOADP_heat represents the heat transfer metric (as defined above) dueto bringing outdoor air into and expelling indoor air out of astructure, i represents an interval,z represents a number of preset timed intervals during the period (theperiod usually being 22 or 24 hours, but could be 6 hours, etc.) whereineach measure of FMOADP_heat is taken.

Similarly, FMOADP_Heat_sum may be calculated using an integralcalculation:

FMOADP_Heat_sum=∫_(a) ^(b)FMOADP_heat(t)dt

wherea=the beginning of the time period,b=the end of the time period, andt=time.

At step 418 of the process 400, the system 10 may calculate a heattransfer metric (HeatTransferred) due to a HVAC unit's operation ofmechanical heating or cooling (e.g. using gas burners, refrigerant basedsystems, etc.), iteratively at predetermined sampling intervals, e.g.,at a time interval as follows, while understandably similar calculationscould be made by replacing the temperature variables for enthalpyvariables and modifying the equations slightly. The operation of themechanical cooling or mechanical heating is preferably considered toascertain the heat transfer into or out of a structure during a periodof time. In a situation where the volumetric air flow (in cubic feet perminute (CFM)) is known, the energy transferred may be fairly easilycalculated, however, in a situation where the CFM is unknown, and forthe purposes of the disclosure, the total heat transfer, as a result ofa HVAC unit's mechanical operation, (e.g., use of gas burners forheating, refrigeration based cooling systems, compressors, etc.) mayrequire the formation of a new metric.

The variable ‘HeatTransferred’ represents a heat transfer metric, due toa HVAC units operation of mechanical heating and/or cooling, but notincluding the heat energy transferred due to bringing outdoor air into,and expelling indoor air out of a structure, and may be determined by:

HeatTransferred=VS*(SAT−RAT)−FMOADP_heat

whereSAT represents a temperature of the supply air from sensor 38,RAT represents a temperature of the return air which may be obtainedfrom sensor 33, andFMOADP_heat=the heat transfer metric (as defined above) due to bringingoutdoor air into, and expelling indoor air out of a structure.

For example, if SAT=100° F., RAT=70° F., VS=1 (on), and FMOADP_heat=−1°F., then: HeatTransferred=1*(100° F.−70° F.)−(−1° F.) which reduces toHeatTransferred=31° F.

FIG. 8B shows an alternative process 400′ for implementation in thesystem 10 without sensors 31, 33, 38, and 39 being used for calculatingHeadTransferred at step 418′. In one embodiment, HeatTransferred may becalculated as follows: HeatTransferred=VS*(Ho−Co), wherein FMODAP heatis equal to zero (step 414′); and Ho represents heating load output andCo represents cooling load output as described hereinabove withreference to FIG. 3. FMOADP_Heat_sum is then calculated at step 416′based upon a FMOADP_heat having a 0 value. As one skilled in the art mayunderstand after considering the teachings disclosed herein that theunits of measurement will change from degree-minutes to minutes. Suchembodiments using this alternative calculation for HeatTransferred shallalso affect the processes, equations, and conclusions given in someparts this disclosure, however, it should be noted that alternativecalculations for HeatTransferred and/or Total_heat_transferred(described below) to operate the system 10 at step 460′, when used inconjunction with the teachings herein disclosed, could effectively beused as understood by those skilled in the art upon a careful reading ofthe teachings herein.

Step 420 of the process 400 may include determining the heat transferreddue to the mechanical operations, e.g., gas burners, refrigerationcircuits, etc., but excluding the heat energy transferred due tointroducing outdoor air into, and expelling indoor air out of thestructure. This value may be calculated for a predefined period (i.e. awhole day, 22 hours, a week, etc.), wherein the calculation is computedonce per interval, and then summed, which may then be represented by thevariable: HeatTransferred_sum, which may then be calculated by:

HeatTransfered_sum≈Σ₁₌₁ ^(z) x _(i) t _(i)

wherei represents an interval or iteration,t_(i) represents a predetermined time intervalx represents HeatTransferred, andz represents a number of preset timed intervals during the period (theperiod usually being 22 or 24 hours, but could be 6 hours, etc.) whereineach measure of HeatTransferred is taken.

Alternatively, the HeatTransferred_sum could be calculated by:

HeatTransferred_sum=∫_(a) ^(b)HeatTransferred(t)dt

wherea=the beginning of the time period,b=the end of the time period, andt=time

In one embodiment, of a structure having a plurality of networkedsystems, a separate HeatTransferred_sum may be determined for eachsystem and then may be added together.

Subsequent to calculating the HeatTransferred_sum, the process 400calculates a Total_heat_transferred (at step 422) by addingHeatTransferred_sum with FMOADP_Heat_sum. Total_heat_transferred thenrepresents a total ° F.-minutes of heat transferred into the structureby the HVAC unit during the time period (i.e. 22 hours, 24 hours, oneweek, etc.). For example: if HeatTransfered_sum=500° F.-minutes,FMOADP_Heat_sum=−400° F.-minutes, then Total_heat_transferred=500°F.-minutes+(−400° F.-minutes)=100° F.-minutes.

In the above example, the heat energy was transferred into the structure(the heating system 12 was operated to introduce heat into thestructure). If the value would have been negative, then heat energywould have been transferred out of the structure by the system 10 viaone or more of the components, e.g., the ventilation system 16.

Once the total_heat_transferred has been determined, it can be used todetermine the slope M 440, which in turn can be used to predict the nextperiod's heat transfer (NTotal_heat_transferred 450). To determine M,the total_heat_transferred for at least two historic time periods can becalculated (i.e. two days, two 6 hour periods, two weeks, or whateverperiod is determined to be most effective in predicting the nextperiod's heat transfer desired). The total_heat_transferred for thefirst historic time period could be total_heat_transferred 1, and forthe second historic time period could be called total_heat_transferred2, and so on, as determined in step 424.

If the volumetric flow rate of the air, based on VS is known, then oneskilled in the art may calculate the heat transfer in British ThermalUnits (BTU) of HeatTransferred, FMOADP_Heat_sum, andTotal_heat_transferred. Integrating the calculations into the system toprovide for automated calculations of HeatTransferred_sum versusFMOADP_Heat_sum would prove beneficial in terms of analyzingdeficiencies in equipment configurations/damper settings (i.e. if astructure was drawing in excessive amounts of outdoor air, etc.).

The process 400 further includes determining an average outdoor airtemperature for a period (AODAT) at steps 430 and 432.

AODAT could be calculated by:

AODAT≦(Σ_(i=1) ^(z) x _(i))/z

whereAODAT represents an average outdoor air temperature for a period,z represents a number of preset timed intervals during the period (theperiod is usually 22 or 24 hours, but could be 6 hours, etc.),x represents an outdoor air temperature, andi represents a predetermined time interval

Alternatively, AODAT may be calculated by:

AODAT=(∫_(a) ^(b) f(x)dx)/(b−a)

wheref(x) represents a function of AODAT measurements over the time period ato b,a represents a beginning of the time period, andb represents an end of the time period.

At steps 434 and 436 of the process 400, iterations of the average spacetemperature inside the structure, e.g., AST1, AST2, etc., may becalculated by:

AST≦(Σ_(i=1) ^(z) x _(i))/z

whereAST represents the average space temperature for a period,z represents a number of preset timed intervals during the period (theperiod usually being 22 or 24 hours, but could be 6 hours, etc.) whereineach measure of the space temperature set point is taken,x represents ST, which is a space temperature measurement made by sensor35, andi represents a predetermined time interval.

Alternatively, the AST could be calculated by:

AST=(∫_(a) ^(b) f(x)dx)/(b−a)

whereAST represents an average space temperature for a period,f(x) represents a function of AST measurements over the time period a tob,a represents a beginning of the time period,b represents an end of the time period, andx represents ST, which is a space temperature measurement made by sensor35.

Considering that it's reasonable to assume that a structure or zone withno internal heat sources, e.g., lights, people, computers, etc., thathas zero influence from radiant heat, e.g., from the sun, that is notaffected by the differential temperatures of materials inside or of thebuilding structure, e.g. the concrete floor, etc., that there is nodifferential temperature between the inside of the structure and theearth, and assuming (for purposes of the process 400), that the HVACequipment, e.g., the exhaust fans 37 and the supply air fans 16, do notadd heat energy to the structure, it's reasonable to assume that thestructure's Total_heat_transferred=0, if the ASTSP=AODAT=AST, where

ASTSP represents the average space temperature set point for a period,AODAT represents the average outdoor air temperature for a period, andAST represents the average space temperature for a period.

Because outdoor air temperatures vary during the course of a period itis beneficial to sample certain variables and values throughout the day.As indicated herein above,Total_heat_transferred=HeatTransferred_sum+FMOADP_Heat_sum. As expressedherein above, a 22 hour, 24 hour, period may be used to define a “day”or “period”, however it should be understood that when determining aslope of a graph, it may be beneficial to use different time periods.For example: While it is understood that HeatTransferred_sum andFMOADP_Heat_sum can use identical time periods for determiningTotal_heat_transferred, and any equations that combineHeatTransferred_sum, FMOADP_Heat_sum, Total_heat_transferred, AODAT, andAST will likely require that identical time periods be used, it shouldalso be understood that in the application of determining the slope((AODAT₂−AST₂)−(AODAT₁−AST₁))/(Total_heat_transferred₂−Total_heat_transferred₁)that smaller time periods may be more suitable, e.g., a 6 hour timeperiod, although the disclosure herein contemplates that various timeperiods may be utilized consistent with the teachings herein.

Subsequent to determining AODAT and AST, the process 400 calculates aslope ‘M’ based upon two or more iterations of AODAT, AST, and theTotal_heat_transferred calculations at step 440.

The slope ‘M’ is the slope of the graph relating Total_heat_transferredto (AODAT−AST), and may be calculated by:

M=((AODAT₂−AST₂)−(AODAT₁−AST₁))/(Total_heat_transferred₂−Total_heat_transferred₁)

whereAST₁ represents an average space temperature for the 1st period,AST₂ represents an average space temperature for the 2nd period,AODAT₁ represents an average outdoor air temperature for the 1st period,AODAT₂ represents an average outdoor air temperature for the 2nd period,andTotal_heat_transferred₁ and Total_heat_transferred₂ being definedhereinabove and having been calculated in step 424.

At step 442 of the process 400, the system 10 may apply variousstatistical conditioning or averaging of the slope M to maintainconsistency. Because the slope of the graph relatesTotal_heat_transferred to (AODAT−AST) it should remain fairly constant,since the slope is directly related to the R-value of the structure'senvelope (as well as other minor factors-in some cases). In oneembodiment, a time period of one week may be used to maintainconsistency/accuracy by averaging M over that time period. M could beaveraged by:

AM≈(Σ_(i=1) ^(z) x _(i))/z

whereAM represents an average of M over time,x represents M, as defined above,z represents a number of preset periods during the time span in which Mis averaged (the time span in which M is averaged could be one week, twoweeks, etc.), andi represents a predetermined interval where each M is calculated.

Under this summation equation, the difference between the beginning ofthe time span and the end of the time span may be defined as a week(i.e., 7 days), while M, could be recalculated every six hours, or oncea day, for example. As noted above, if slope M is to be calculated everysix hours, then the subsequent periods within the calculations forAODAT, AST, and Total_heat_transferred would preferentially use six-hourtime periods, where appropriate. AM may be calculated using thefollowing equation:

AM=(∫_(a) ^(b) f(x)dx)/(b−a)

whereWhere f(x) represents a function of m slope calculations over the timespan a to b,a represents a beginning of the time span, andb represents an end of the time span.

With reference to FIG. 9, B is a y-intercept used on FIG. 9 thatillustrates a relationship of Total_heat_transferred to (AODAT−AST). Atstep 444 of process 400, B may be calculated for a time period, i, bythe equation:

B=(AODAT_(i)−AST_(i))−(Total_heat_transferred_(i) *M _(i))

whereAODAT represents average outdoor air temperature, as defined previously,AST represents average space temperature, as defined previously,i represents a predetermined interval where each B is calculated, andM represents a slope of the graph comparing Total_heat_transferred to(AODAT-AST).

Similar to calculating AM, an average B could be calculated over a timespan. Average B, represented as AB, may be calculated in step 446 of theprocess 400 using:

AB≈(Σ_(i=1) ^(z) x _(i))/z

whereAB represents an average of B over time,x represents B, as defined above,z represents a number of preset periods during the time span in which Bis averaged (the time span in which B is averaged could be one week, twoweeks, etc.), andi represents a predetermined interval where each B is calculated.

In one embodiment, AB could be calculated by one or more variations of:

AB=(∫_(a) ^(b) f(x)dx)/(b−a)

wheref(x) represents a function of y-intercept (B) calculations over a timespan a to b,a represents a beginning of the time span, andb represents an end of the time span.

Subsequent to determining the AM slope and AB (the average y-interceptof FIG. 9), the process continues to step 450 wherein aNTotal_heat_transferred value is determined. In various embodiments,weather predictions may be utilized in conjunction with the AM slope todetermine the next period's (e.g., day), anticipated/projectedTotal_heat_transferred, i.e., NTotal_heat_transferred. In someembodiments, the AM slope permits incorporating set point data into theequation for determining the next day's anticipated/projectedTotal_heat_transferred. For example: a church may not have need forcooling any day except Sunday. Such as this is the case, it's likelythat the parishioners would set the thermostat to a very hightemperature set point for all days except for Sunday. Assuming that thespace temperature will need to reach the space temperature set point, wecan use the slope to determine the NTotal_heat_transferred.

A predicted space temperature may be determined by taking all relevantdata regarding scheduled set point information (which correlates spacetemperature set points with times), default space temperature setpoints, historical user set point data, etc. Although the usualday/night temperature swing which occurs will lead to many embodimentssimply having a daily time period, one skilled in the art may envisionan embodiment configured, such that energy may be stored, in a region ofthe world like Antarctica, wherein the period may be generally extendedfor the entire warm season, which would be the summer. Such as thenormal one-day embodiment will be the case, the calculation of ASTSP, isprovided as an exemplary embodiment for an exemplary application,normally being about one day, however it should be understood by thoseskilled in the art that the one day examples given herein are notintended to limit the scope of the disclosure. ASTSP, generally, mayinclude the average space temperature set points for the next period andmay be calculated by:

ASTSP≈(Σ_(i=1) ^(z) x _(i))/z

whereASTSP represents an average space temperature set point for a period,z represents a number of preset timed intervals during the period(usually 22 or 24 hours, but could be 6 hours, etc.) wherein eachmeasure of the space temperature set point is taken,x represents the space temperature set point, andi represents a predetermined time interval.

Alternatively, the ASTSP could be calculated by:

ASTSP=(∫_(a) ^(b) f(x)dx)/(b−a)

wheref(x) is a function of space temperature set points from a to b,a represents a beginning of the time period,b represents an end of the time period.

PAODAT is the predicted average outdoor air temperature. In oneembodiment, this value may be determined from an average of thepredicted outdoor air temperatures (PODAT) over a future time period. Inone embodiment, PAODAT may be based upon forecasted predictions fromsubscription or governmental sources, e.g., weather forecastinginformation. In one embodiment, PAODAT may simply be based upon arolling average temperature period over a predefined number of timeperiods, e.g., days. As there are many ways to determine PAODAT, whichone skilled in the art will recognize upon a careful reading of thedisclosure herein may understand there are many ways to determinePAODAT.

PAST is the predicted average space temperature for the following timeperiod (i.e. the next day or next 12 hours, etc.). There are many waysto calculate PAST. In one embodiment of the invention, PAST may be equalto the AST of a chosen historical time period, such as the day before,or the same day of the previous week. The limitation of setting PASTequal to a previous time period's AST is that this method does not takeinto account the future set point temperature schedule.

In one embodiment, PAST is a function of predicted outdoor airtemperature (PODAT) and the future set point temperature. Usinghistorical data, the space temperature could be plotted versus theoutdoor air temperature under different set point temperatureconditions. From this data, functions to represent ST versus ODAT, underdifferent set point conditions, could be determined. Any data thatderives a non-functional result would be negated or accounted fordifferently. Next, the PODAT could be substituted for the ODAT in thefunctions. In one embodiment, PAST can be calculated as follows:

${PAST} = {\left( \frac{1}{{T\; 1} + {T\; 2} + \ldots + {Tn}} \right)\left( {{T\; 1*\frac{\int_{a\; 1}^{b\; 1}{\left( {f(x)} \right)1\ {x}}}{{b\; 1} - {a\; 1}}} + {T\; 2*\frac{\int_{a\; 1}^{b\; 1}{\left( {f(x)} \right)2\ {x}}}{{b\; 2} - {a\; 2}}} + \ldots + {{Tn}*\frac{\int_{a\; n}^{b\; n}{\left( {f(x)} \right)n\ {x}}}{{b\; n} - {a\; n}}}} \right)}$

wherex represents a predicted outdoor air temperature (POADT),(f(x))1, (f(x))2 . . . (f(x))n represent a function of space temperaturebased on POADT, wherein the function may be different for every setpoint temperature,T1, T2 . . . Tn represent time intervals in which the set pointtemperature remains a constant (i.e. for the first 4 hours (T1=4) of theday the set point is at 70° F., for the next 6 hours (T2=6) the setpoint is 72° F., etc.),n represents a total number of set point intervals for the time period(i.e. day, 12 hours, etc.),b1, b2, bn represent an ending POADT of the interval, anda1, a2, an represent a beginning POADT of the interval.

In one embodiment, PAST may be calculated based upon Newton's

“Law of Cooling (Warming).” Newton's “Law of Cooling” states that therate at which the temperature changes of one body is proportional to thedifference in the temperatures of the body and the environment. In thisapplication, the environment includes the outside as well as the effectsof internal heat sources, such as computers, lights, etc. Thedifferential equation for Newton's “Law of Cooling” is as follows:

$\frac{({ST})}{t} = {k\left( {{{ODAT}\; 1} - {ST}} \right)}$

Accounting for internal heat sources:

$\frac{({ST})}{t} = {k\left( {{{YODAT}\; 1} - {ST}} \right)}$

where

$\frac{({ST})}{t}$

represents a rate of change of temperature with respect to time,k represents a proportionality constant,t represents time,YODAT1 represents the outdoor air temperature minus the value of theabove B or AB at the start of the time interval, andST represents a space temperature at any time t.

We will begin by assuming that the building is warming up andYODAT1>ST1. This differential equation is solved by separating thevariables:

$\frac{({ST})}{\left( {{{YODAT}\; 1} - {ST}} \right)} = {k{t}}$

and then integrating

${\int\frac{({ST})}{\left( {{{YODAT}\; 1} - {ST}} \right)}} = {\int{k{t}}}$ln YODAT 1 − ST = kt + c

wherec represents a constant obtained in any antiderivative.

Solve for ST via exponentials on both sides of the equation:

YODAT1−ST=e ^(kt+c)

YODAT1−ST=(e ^(kt))(e ^(c))

Since c is a constant, e^(c) is also a constant, hereinafter referred toas: C and the equation becomes:

YODAT1−ST=Ce ^(kt).

By solving for ST, the equation may be represented as:

ST=YODAT1−Ce ^(kt).

In predicting how the structure responds to temperature changes, both kand C can be determined. Two data points are used to determine how thestructure naturally warms. Using historical data (t1, ST1) and (t2, ST2)where the numbers 1 and 2 indicate first and second data points whileYODAT1 remains constant.

These data points are inserted into the solved differential equation toobtain two equations with the same two unknowns, k and C.

ST1=YODAT1−Ce ^(k(t1))

ST2=YODAT1−Ce ^(k(t2))

To simply solve for k and C, we can assume that t1=0.

ST1=YODAT1−Ce ^(k(0))

ST1=YODAT1−C

C=YODAT1−ST1

and C is simply the difference in the initial indoor and outdoortemperatures minus the value of B or AB.

Substituting this value of C into the same equation with the second datapoint, we can solve for k.

ST 2 = YODAT 1 − (YODAT 1 − ST 1)^(k(t 2))$\frac{{{ST}\; 2} - {{YODAT}\; 1}}{- \left( {{{YODAT}\; 1} - {{ST}\; 1}} \right)} = ^{k{({t\; 2})}}$${\ln \left( \frac{{{ST}\; 2} - {{YODAT}\; 1}}{- \left( {{{YODAT}\; 1} - {{ST}\; 1}} \right)} \right)} = {k\left( {t\; 2} \right)}$$k = \frac{\ln \left( \frac{{{ST}\; 2} - {{YODAT}\; 1}}{- \left( {{{YODAT}\; 1} - {{ST}\; 1}} \right)} \right)}{\left( {t\; 2} \right)}$

If t1≠0, then we can transform the equations removing the exponentialsto solve for k and C. First, substitute the two data points to obtaintwo equations.

YODAT1−ST1=Ce ^(k(t1))

YODAT1−ST2=Ce ^(k(t2))

We now take the natural logarithm of both sides.

ln(YODAT1−ST1)=ln(Ce ^(k(t1)))

ln(YODAT1−ST1)=ln(C)+ln(e ^(k(t1)))

ln(YODAT1−ST1)=ln(C)+k(t1)

We use the same process with the second equation to obtain:

ln(YODAT1−ST2)=ln(C)+k(t2).

Using the method of elimination, we first solve for k. One equation issubtracted from the other and the common term ln(C) is eliminatedyielding:

ln (YODAT 1 − ST 2) − ln (YODAT 1 − ST 1) = k(t 2) − k(t 1)ln (YODAT 1 − ST 2) − ln (YODAT 1 − ST 1) = k(t 2 − t 1)$k = \frac{{\ln \left( {{{YODAT}\; 1} - {{ST}\; 2}} \right)} - {\ln \left( {{{YODAT}\; 1} - {{ST}\; 1}} \right)}}{\left( {{t\; 2} - {t\; 1}} \right)}$$k = \frac{\ln \left( \frac{{{YODAT}\; 1} - {{ST}\; 2}}{{{YODAT}\; 1} - {{ST}\; 1}} \right)}{\left( {{t\; 2} - {t\; 1}} \right)}$

Knowing the value of k, we can substitute this value and solve for C:

     ln (YODAT 1 − ST 1) = ln (C) + kt₁${\ln \left( {{{YODAT}\; 1} - {{ST}\; 1}} \right)} = {{\ln (C)} + {\frac{{\ln \left( {{{YODAT}\; 1} - {{ST}\; 2}} \right)} - {\ln \left( {{{YODAT}\; 1} - {{ST}\; 1}} \right)}}{\left( {{t\; 2} - {t\; 1}} \right)}\left( {t\; 1} \right)}}$${\ln (C)} = {{\ln \left( {{{YODAT}\; 1} - {{ST}\; 1}} \right)} - {\frac{{{\ln \left( {{{YODAT}\; 1} - {{ST}\; 2}} \right)} - {\ln \left( {{{YODAT}\; 1} - {{ST}\; 1}} \right)}}\;}{\left( {{t\; 2} - {t\; 1}} \right)}\left( {t\; 1} \right)}}$$\mspace{79mu} {C = ^{\lbrack{{\ln {({{{YODAT}\; 1} - {{ST}\; 1}})}} - {\frac{{\ln {({{{YODAT}\; 1} - {{ST}\; 2}})}} - {\ln {({{{YODAT}\; 1} - {{ST}\; 1}})}}}{({{t\; 2} - {t\; 1}})}{({t\; 1})}}}\rbrack}}$$\mspace{79mu} {C = ^{\lbrack{{\ln {({{{YODAT}\; 1} - {{ST}\; 1}})}} - {\frac{\ln {(\frac{{{YODAT}\; 1} - {{ST}\; 2}}{{{YODAT}\; 1} - {{ST}\; 1}})}}{({{t\; 2} - {t\; 1}})}{({t\; 1})}}}\rbrack}}$

The value of k is a value dependent on the thermal characteristics ofthe structure. The value C would be calculated with different values ofYODAT1 and ST1.

When the outside temperature minus the above B or AB is less than theinside temperature (YODAT2<ST1, where YODAT2 is the outdoor airtemperature minus either B or AB, the structure will naturally cool.Again, we start with Newton's “Law of Cooling”:

$\frac{({ST})}{t} = {{k\left( {{ST} - {{YODAT}\; 2}} \right)}.}$

whereYODAT2 represents the outdoor air temperature minus the value of above Bor AB at the start of the time interval.

Separate the variables and integrate as before:

${\int\frac{({ST})}{{ST} - {{YODAT}\; 2}}} = {\int{k{t}}}$ln ST − YODAT 2 = kt + c ST − YODAT 2 = ^(kt + c)ST − YODAT 2 = Ce^(kt) ST = Ce^(kt) + YODAT 2

Two data points are used to determine how the structure naturally cools.Using historical data (t1, ST1) and (t2, ST2) where the numbers 1 and 2are the labels for the first and second data points while YODAT2 remainsconstant. These data points are inserted into the above solveddifferential equation to obtain two equations with the same twounknowns, k and C.

ST1=Ce ^(k)(t1)+YODAT2

ST2=Ce ^(k)(t2)+YODAT2

To simply solve for k and C, we can assume that t1=0.

ST1=Ce ^(k)(0)+YODAT2

ST1=C+YODAT2

C=ST1−YODAT2

Where C is the difference in the initial indoor and outdoor temperaturesminus the y-intercept (B or AB—as defined herein above) of FIG. 9 forthe start of the period of structural cooling.

Substituting this value of C into the same equation with the second datapoint, we can solve for k.

ST 2 = (ST 1 − YODAT 2)^(k(t 2)) + YODAT 2$\frac{{{ST}\; 2} - {{YODAT}\; 2}}{{{ST}\; 1} - {{YODAT}\; 2}} = ^{k{({t\; 2})}}$${\ln \left( \frac{{{ST}\; 2} - {{YODAT}\; 2}}{{{ST}\; 1} - {{YODAT}\; 2}} \right)} = {k\left( {t\; 2} \right)}$$k = \frac{\ln \left( \frac{{{ST}\; 2} - {{YODAT}\; 2}}{{{ST}\; 1} - {{YODAT}\; 2}} \right)}{\left( {t\; 2} \right)}$

If t1≠0, then we can transform the equations removing the exponentialsto solve for k and C as before.

ST1−YODAT2=Ce ^(k(t1))

ST2−YODAT2=Ce ^(k(t2))

We may now take the natural logarithm of both sides.

ln(ST1−YODAT2)=ln(Ce ^(k(t1)))

ln(ST1−YODAT2)=ln(C)+ln(e ^(k(t1)))

ln(ST1−YODAT2)=ln(C)+k(t1)

We use the same process with the second equation to obtain

ln(ST2−YODAT2)=ln(C)+k(t2).

Using the method of elimination, we first solve for k. One equation issubtracted from the other and the common term ln(C) is eliminatedyielding

ln (ST 2 − YODAT 2) − ln (ST 1 − YODAT 2) = k(t 2) − k(t 1)ln (ST 2 − YODAT 2) − ln (ST 1 − YODAT 2) = k(t 2 − t 1)$k = \frac{{\ln \left( {{{ST}\; 2} - {{YODAT}\; 2}} \right)} - {\ln \left( {{{ST}\; 1} - {{YODAT}\; 2}} \right)}}{\left( {{t\; 2} - {t\; 1}} \right)}$$k = \frac{\ln \left( \frac{{{ST}\; 2} - {{YODAT}\; 2}}{{{ST}\; 1} - {{YODAT}\; 2}} \right)}{\left( {{t\; 2} - {t\; 1}} \right)}$

Knowing the value of k, we can substitute this value and solve for C.

     ln (ST 1 − YODAT 2) = ln (C) + kt₁${\ln \left( {{{ST}\; 1} - {{YODAT}\; 2}} \right)} = {{\ln (C)} + {\frac{{\ln \left( {{{ST}\; 2} - {{YODAT}\; 2}} \right)} - {\ln \left( {{{ST}\; 1} - {{YODAT}\; 2}} \right)}}{\left( {{t\; 2} - {t\; 1}} \right)}\left( {t\; 1} \right)}}$${\ln (C)} = {{\ln \left( {{{ST}\; 1} - {{YODAT}\; 2}} \right)} - {\frac{{{\ln \left( {{{ST}\; 2} - {{YODAT}\; 2}} \right)} - {\ln \left( {{{ST}\; 2} - {{YODAT}\; 2}} \right)}}\;}{\left( {{t\; 2} - {t\; 1}} \right)}\left( {t\; 1} \right)}}$$\mspace{79mu} {C = ^{\lbrack{{\ln {({{{ST}\; 1} - {{YODAT}\; 2}})}} - {\frac{{\ln {({{{ST}\; 2} - {{YODAT}\; 2}})}} - {\ln {({{{ST}\; 1} - {{YODAT}\; 2}})}}}{({{t\; 2} - {t\; 1}})}{({t\; 1})}}}\rbrack}}$$\mspace{79mu} {C = ^{\lbrack{{\ln {({{{ST}\; 1} - {{YODAT}\; 2}})}} - {\frac{\ln {(\frac{{{ST}\; 2} - {{YODAT}\; 2}}{{{ST}\; 1} - {{YODAT}\; 2}})}}{({{t\; 2} - {t\; 1}})}{({t\; 1})}}}\rbrack}}$

We will use as an example three intervals to see how PAST can becalculated: naturally warming, maintaining set point (STSP), andnaturally cooling. Space temperature (ST) is a function of time (t).

${{ST}(t)} = \left\{ \begin{matrix}{{{YODAT}\; 1} - {Ce}^{kt}} & {{t\; 1} \leq t < {t\; 2}} \\{STSP} & {{t\; 2} \leq t < {t\; 3}} \\{{Ce}^{kt} + {{YODAT}\; 2}} & {{t\; 3} \leq t \leq {t\; 4}}\end{matrix} \right.$

whereSTSP represents space temperature set point.

Knowing the value of k for warming and cooling, we can predict PAST. Inone instance as FIGS. 10A and 10B illustrate, there may be a period ofnatural warming, a steady period (temperature at STSP), and a period ofnatural cooling. Finding the average (PAST) may be done the followingway:

$\begin{matrix}{{PAST} = {\frac{1}{{t\; 4} - {t\; 1}}{\int_{t\; 1}^{t\; 4}{{{ST}(t)}\ {t}}}}} \\{= {\frac{1}{{t\; 4} - {t\; 1}}\begin{bmatrix}{{\int_{t\; 1}^{t\; 2}{\left( {{{YODAT}\; 1} - {Ce}^{kt}} \right){t}}} +} \\{{\int_{t\; 2}^{t\; 3}{({STSP})\ {t}}} + {\int_{t\; 3}^{t\; 4}{\left( {{Ce}^{kt} + {{YODAT}\; 2}} \right){t}}}}\end{bmatrix}}}\end{matrix}\quad$

Using the value of k from the historical data and the difference inindoor and outdoor temperatures (plus the value of B or AB), we canpredict when the ST of the structure will be at STSP as the buildingwarms using: STSP=YODAT1−Ce^(kt). Solve for t. This is t2. This definesan interval of natural structural warming [t1, t2].

While the structure is at STSP and the cooling system cycles, this willdefine the next interval [t2, t3] as the value of t3 can be obtainedfrom predicted weather (the time at which YODAT2=STSP) after the heat ofthe day (YODAT2 being the outdoor air temperature minus the value ofabove B or AB).) The interval of time through which the structurenaturally cools will define the third interval [t3, t4]. t4 would be thetime at which the outdoor ambient conditions are desirable to conditionthe structure. Again, t4 can be obtained from predicted hourly weather(hourly, minutely, etc.) and may be set, in one embodiment, to a time atwhich it is desirable to condition the space. In another embodiment, t4may be a time at which YODAT=STSP, etc.

The expansion of each interval in the calculation of PAST is shownbelow.

$\begin{matrix}\begin{matrix}{{\int_{t\; 1}^{t\; 2}{\left( {{{YODAT}\; 1} - {Ce}^{kt}} \right){t}}} = {{\int_{t\; 1}^{t\; 2}{\left( {{YODAT}\; 1} \right){t}}} - {\int_{t\; 1}^{t\; 2}{\left( {Ce}^{kt} \right){t}}}}} \\{= {\left( {{YODAT}\; 1} \right)t{_{t\; 1}^{t\; 2}{{- \frac{C}{k}}\left( ^{kt} \right)}}_{t\; 1}^{t\; 2}}} \\{= {{\left( {{YODAT}\; 1} \right)\left( {{t\; 2} - {t\; 1}} \right)} - {\frac{C}{k}\left( {^{k{({t\; 2})}} - ^{k{({t\; 1})}}} \right)}}}\end{matrix} & \; \\\begin{matrix}{{\int_{t\; 2}^{t\; 3}{({STSP})\ {t}}} = {({STSP})t_{t\; 2}^{t\; 3}}} \\{= {{({STSP})\left( {t\; 3} \right)} - {({STSP})\left( {t\; 2} \right)}}} \\{= {{STSP}\left( {{t\; 3} - {t\; 2}} \right)}}\end{matrix} & \; \\\begin{matrix}{{\int_{t\; 3}^{t\; 4}{\left( {{Ce}^{kt} + {{YODAT}\; 2}} \right){t}}} = {{\int_{t\; 3}^{t\; 4}{\left( {Ce}^{kt} \right){t}}} + {\int_{t\; 3}^{t\; 4}{\left( {{YODAT}\; 2} \right){t}}}}} \\{= {\frac{C}{k}\left( ^{kt} \right){_{t\; 3}^{t\; 4}{{+ \left( {{YODAT}\; 2} \right)}t}}_{t\; 3}^{t\; 4}}} \\{= {{\frac{C}{k}\left( {^{k{({t\; 4})}} - ^{k{({t\; 3})}}} \right)} + {\left( {{YODAT}\; 2} \right)\left( {{t\; 4} - {t\; 3}} \right)}}}\end{matrix} & \;\end{matrix}$

When considering the teachings herein above, one skilled in the artcould determine PAST using the conditional processes described hereinabove for various scenarios.

The predicted average space temperature (PAST) for the next period, e.g.the next day, could be extracted from a user-supplied temperatureschedule, default temperature schedule, historical user entry data, acombination of these, the equations given herein above, etc. TheNTotal_heat_Transferred value is that which the system 10 would try toachieve in order to condition the structure in preparation of the nextday, however, upper and lower limits may inhibit the value being toohigh or low, and/or upper and lower limits may inhibit the operations toachieve NTotal_heat_Transferred in order to keep the space temperaturewithin reasonable limits. The appropriate limits on the operations ofthe systems may be understood by one skilled in the art, whenconsidering the teachings herein disclosed.

In one embodiment, NTotal_heat_Transferred may be calculated by:

NTotal_heat_Transferred=((PAODAT−PAST)−AB)/AM

whereAM represents an average M, as previously defined,AB represents an average B, as previously defined,PAODAT represents a predicted average outdoor air temperature, andPAST represents a predicted average space temperature over a period.

If volumetric flow rates of the system 10 are known in real units ofmeasure (i.e. CFM),) then industry standard calculations could be madeto determine the real value, in terms of real units of measure (i.e.BTU), of heat transfer. Also an amount of energy produced inside thestructure due to people, computers, lights, etc., which is referred toas IHEPIS (the value of the x-intercept of the graph in FIG. 9multiplied by −1) could be calculated using real units of measure (e.g.,BTU's). Also, if the surface area of the structure's envelope is known,then the R-value of the structure's envelope could be computed using theslope of (AODAT−AST)/Total_heat_transferred, although if for instance awindow was left open, the resulting heat transfer would affect thecalculated R-value.

Additionally, k could be used to calculate the effective thermalcapacity of the structure.

Subsequent to determining NTotal_heat_Transferred, the system 10 mayoperate various components to effect ventilation, cooling, and/orheating at step 460 based upon the calculated NTotal_heat_Transferredvalue. In a simplified example, the following table shows the AODAT,AST, and total_heat_transferred over three days (i.e. three timeperiods). Please note that this example may not be typical, but ratheris given for illustrative purposes.

Day Monday Tuesday Wednesday AODAT 70° F. 90° F. 50° F. AST 68° F. 68°F. 68° F. Total_heat_trans-  −100° F.-min  −600° F.-min   200° F.-minferredIn this example, M1 is the slope for the graph comparingTotal_heat_transferred to (AODAT−AST) from Monday to Tuesday, and M2 isthe slope from Tuesday to Wednesday. M1 and M2 may be calculated as:

M1=((70−68)−(90−68))/((−100)−(−600))=−1/25

M2=((90−68)−(50−68))/((−600)−200)=−1/20

Therefore, the average slope, AM=((−1/25)+(−1/20))/2=−0.045. Next, they-intercept (B1) from Monday to Tuesday, and B2 from Tuesday toWednesday would be calculated as follows:

B1=(70−68)−(−100)*(−1/25)=−2° F.

B2=(50−68)−(200)*(−1/20)=−8° F.

Therefore, the average B, AB=((−2)+(−8))/2=−5° F.

If PAODAT for Thursday was calculated as 75° F., and PAST for Thursdaywas calculated as 68° F., NTotal_heat_transferred could be calculatedfor this example as:

NTotal_heat_transferred=((75−68)−(−5))/(−0.045)=−267° F.-min.

This means that the system would cool the structure on Thursday,transferring −267° F.-min of heat energy to do so. Therefore, during thetime when conditions were optimal (usually from 4-6 am), the systemwould bring in cool outdoor air for a certain amount of time until thetotal_heat_transferred reached the −267° F.-min necessary to meet theday's predicted cooling requirements. Alternatively, the system couldalso activate mechanical cooling (i.e. compressors, refrigerationsystems, etc.) to cool the structure. If NTotal_heat_transferred were apositive value, then the system could heat the structure instead ofcooling it. If opportune, this could be done during the heat of the dayby bringing in outdoor air and exhausting indoor air, or alternatively,with mechanical heating (i.e. heat pumps, etc.) if conditions warrantedsuch action.

The internal heat energy produced inside a structure, due to things likelighting, computers, etc. is referred to herein as: “IHEPIS”.

In order to model IHEPIS, at least two periods with varyingTotal_heat_transferred and (AODAT−AST) values may be used in order todetermine a slope M, which has a correlation to the R-value of thatstructure's envelope. IHEPIS may be calculated as the value of −1multiplied by the x-intercept of the graph, shown as exemplary FIG. 9comparing Total_heat_transferred to (AODAT−AST). Once the average slope(AM) and average y-intercept (AB) are known over a time span, IHEPIScould be calculated as:

IHEPIS=−1*(−AB/AM)

whereAB=average y-intercept B, as defined previously, andAM=average slope M, as defined previously.

As one skilled in the art will readily understand upon a careful readingof the teachings herein, space temperature set point may be used ratherthan space temperature to operate many of the functions, calculations,and equations disclosed herein.

The disclosure has described certain preferred embodiments andmodifications thereto. Further modifications and alterations may occurto others upon reading and understanding the specification. Therefore,it is intended that the disclosure not be limited to the particularembodiment(s) disclosed for carrying out this disclosure, but that thedisclosure will include all embodiments falling within the scope of theappended claims.

1. A method for operating a temperature control system having aventilation subsystem and a cooling subsystem, the method comprising:monitoring an indoor temperature of a structure; monitoring an outdoortemperature of ambient air outside of the structure; defining a firsttime range and a second time range, wherein the second time rangecomprises a duration less than the first time range; associating one ormore operating parameters of the ventilation subsystem and the coolingsubsystem with the first time range; associating one or more operatingparameters of the ventilation subsystem and the cooling subsystem withthe second time range; monitoring operational time and operational loadof the cooling subsystem for the first time range; predicting a spacetemperature and an outdoor air temperature for a subsequent time period;and controlling the ventilation subsystem during the second time rangebased upon the monitored operational time and operational load of thecooling subsystem for the first time range, the monitored interior andexterior temperatures, the predicted space temperature, the predictedoutdoor air temperature, and the one or more operating parameters of thecooling subsystem associated with the second time range.
 2. The methodof claim 1, wherein the predicting the space temperature is predictedbased upon the monitored indoor and outdoor temperature of one or moreprior defined time periods, a user-supplied temperature set point(s)associated with the one or more prior defined time periods, and thepredicted outdoor air temperature.
 3. The method of claim 1, wherein thepredicting the space temperature is predicted based upon the monitoredindoor and outdoor temperature of one or more prior defined timeperiods, a user-supplied temperature set point(s) associated with theone or more prior defined time periods, and the predicted outdoor airtemperature.
 4. The method of claim 3, wherein the predicting a spacetemperature is calculated using:$\left( \frac{1}{{T\; 1} + {T\; 2} + \ldots + {Tn}} \right)\left( {{T\; 1*\frac{\int_{a\; 1}^{b\; 1}{\left( {f(x)} \right)1{x}}}{{b\; 1} - {a\; 1}}} + {T\; 2*\frac{\int_{a\; 1}^{b\; 1}{\left( {f(x)} \right)2{x}}}{{b\; 2} - {a\; 2}}} + \ldots + {{Tn}*\frac{\int_{an}^{bn}{\left( {f(x)} \right)n{x}}}{{bn} - {an}}}} \right)$where x represents the predicted outdoor air temperature (POADT),(f(x))1, (f(x))2 . . . (f(x))n represent a function of spacetemperature, T1, T2 . . . Tn represent time intervals, n represents atotal number of set point intervals for the time period, b1, b2, bnrepresent an ending POADT of the interval, and a1, a2, an represent abeginning POADT of the interval.
 5. The method of claim 1, furthercomprising: monitoring a supply air temperature and a return airtemperature; monitoring an operating status of a ventilation system;monitoring space temperature; calculating a first average spacetemperature for a first time period based upon the monitored inside airtemperature; calculating a second average space temperature for a secondtime period based upon the monitored inside air temperature; calculatinga first average outdoor air temperature for the first time period basedupon the monitored outdoor air temperature; calculating a second averageoutdoor air temperature for the second time period based upon themonitored outdoor air temperature; and further controlling thetemperature control system based upon the supply air temperature, thereturn air temperature, the monitored space temperature; the operatingstatus of the ventilation system, the calculated first average spacetemperature, the calculated second average space temperature, thecalculated first average outdoor air temperature, and the calculatedsecond average outdoor air temperature.
 6. The method of claim 5,wherein the temperature control system further includes an outdoor airdamper; and wherein the method further includes: monitoring a mixed airtemperature, wherein the mixed air temperature is monitored within ahousing of the temperature control, downstream of a return air supplyand downstream of outside air; calculating an opening position of theoutdoor air damper based upon the monitored return air temperature, themonitored mixed air temperature, and the monitored outdoor temperature;and further controlling the temperature control system based upon themonitored opening position.
 7. The method of claim 6, whereincontrolling the temperature control system further includes:iteratively, at defined time periods, summing, for a first result, aproduct of the monitored operating status of the ventilation system witha difference of the supply air temperature and the monitored return airtemperature and a difference of a product of the monitored operatingstatus of the ventilation system and the calculated opening position ofthe outdoor air damper with a difference of the monitored outdoortemperature and the monitored return air temperature; furthercontrolling the temperature control system based upon the iterativelysumming; iteratively, at defined time periods, summing, for a secondresult, a product of the monitored operating status of the ventilationsystem and the monitored opening position of the outdoor air damper witha difference of the monitored outdoor temperature and the monitoredreturn air temperature; and further controlling the temperature controlsystem based upon the iteratively summing.
 8. The method of claim 7,wherein controlling the temperature control system further includes:further controlling the temperature control system based upon a sum ofthe first result and the second result; and averaging a differencebetween the first average outdoor air temperature and the first averagespace temperature subtracted from a product of the sum of the firstresult and the second result and a variable M calculated by: adifference between the difference of the second average outdoor airtemperature for the second time period and the second average spacetemperature for the second time period and the difference between thefirst average outdoor air temperature for the first time period and thefirst average space temperature for the first time period divided by: adifference between the sum of the first result and the second resultcalculated at the second time period and the sum of the first result andthe second result calculated at the first time period.
 9. The method ofclaim 1, further comprising: monitoring a mixed air temperature, whereinthe mixed air temperature is monitored within a housing of thetemperature control, downstream of a return air supply and downstream ofoutside air; calculating an opening position of the outdoor air damperbased upon the monitored return air temperature, the monitored mixed airtemperature, and the monitored outdoor temperature; further controllingthe temperature control system based upon the calculated damperposition.
 10. The method of claim 1, further comprising: estimating heatenergy produced inside the structure based upon the monitored outdoorair temperatures, the monitored indoor air temperatures, and operatingstatus of the temperature control system; and further controlling thetemperature control system based upon the estimated heat energyproduced.
 11. A method for operating a temperature control system for astructure, the method comprising: monitoring indoor and outdoortemperature; monitoring an operating state of the temperature controlsystem; predicting a space temperature and an outdoor air temperaturefor a subsequent time period; estimating an operating metric fortemperature control system based upon the (a) monitored interiortemperature of the structure, (b) monitored outside air temperature, (c)monitored operating state of the temperature control system, (d)predicted space temperature, and (e) predicted outdoor air temperature;and controlling the temperature control system during the subsequenttime period based upon the estimated operating metric.
 12. The method ofclaim 11, wherein the operating state of the temperature control systemis one of an ON operating state or an OFF operating state for each of aheating system, a cooling system, and a ventilation system.
 13. Themethod of claim 11, wherein the predicting the space temperature ispredicted based upon the monitored indoor temperature of a prior definedtime period and user-supplied temperature set point(s).
 14. The methodof claim 11, wherein the predicting the space temperature is an averagetemperature of a prior defined time period.
 15. The method of claim 11,wherein the predicting a space temperature is predicted based upon thepredicted outdoor air temperature, the monitored outdoor airtemperature, and user-supplied temperature set points.
 16. The method ofclaim 11, wherein the predicting the space temperature is predictedbased upon the monitored indoor and outdoor temperature of one or moreprior defined time periods, a user-supplied temperature set point(s)associated with the one or more prior defined time periods, and thepredicted outdoor air temperature.
 17. The method of claim 11, whereinthe predicting a space temperature is calculated using:$\left( \frac{1}{{T\; 1} + {T\; 2} + \ldots + {Tn}} \right)\left( {{T\; 1*\frac{\int_{a\; 1}^{b\; 1}{\left( {f(x)} \right)1{x}}}{{b\; 1} - {a\; 1}}} + {T\; 2*\frac{\int_{a\; 1}^{b\; 1}{\left( {f(x)} \right)2{x}}}{{b\; 2} - {a\; 2}}} + \ldots + {{Tn}*\frac{\int_{an}^{bn}{\left( {f(x)} \right)n{x}}}{{bn} - {an}}}} \right)$where x represents the predicted outdoor air temperature (POADT),(f(x))1, (f(x))2 . . . (f(x))n represent a function of spacetemperature, T1, T2 . . . Tn represent time intervals, n represents atotal number of set point intervals for the time period, b1, b2, bnrepresent an ending POADT of the interval, and a1, a2, an represent abeginning POADT of the interval.
 18. The method of claim 11, wherein thepredicting a space temperature is calculated using: $\begin{matrix}{{PAST} = {\frac{1}{{t\; 4} - {t\; 1}}{\int_{t\; 1}^{t\; 4}{{{ST}(t)}{t}}}}} \\{= {\frac{1}{{t\; 4} - {t\; 1}}\begin{bmatrix}{{\int_{t\; 1}^{t\; 2}{\left( {{{YODAT}\; 1} - {Ce}^{kt}} \right){t}}} +} \\{{\int_{t\; 2}^{t\; 3}{({STSP}){t}}} + {\int_{t\; 3}^{t\; 4}{\left( {{Ce}^{kt} + {{YODAT}\; 2}} \right){t}}}}\end{bmatrix}}}\end{matrix}\quad$ where PAST represents the predicting a spacetemperature, $\frac{({ST})}{t}$ represents a rate of change oftemperature with respect to time, STSP represents space temperature setpoint, ST represents a space temperature at any time t, wherein ST=STSPwhen STSP=YODAT1−C ê(kt) k represents a proportionality constant, trepresents time, YODAT1 represents the outdoor air temperature plus thevalue of B at the start of the time interval, YODAT2 represents theoutdoor air temperature plus the value of B at the start of the secondtime interval, and C is constant and whereB=(AODAT_(i)−AST_(i))−(Total_heat_transferred_(i) *M _(i)) where AODATrepresents average outdoor air temperature, as defined previously, ASTrepresents average space temperature, as defined previously, irepresents a predetermined interval where each B is calculated, and Mrepresents a slope of the graph comparing Total_heat_transferred to(AODAT−AST).
 19. The method of claim 11, wherein the predicting theoutdoor air temperature is executed based upon received weatherforecasting information.
 20. The method of claim 11, wherein thepredicting the outdoor air temperature is determined based upon arolling average of the monitored outdoor air temperature.
 21. The methodof claim 11, further comprising: monitoring a supply air temperature anda return air temperature; monitoring an operating status of aventilation system; monitoring space temperature; calculating a firstaverage space temperature for a first time period based upon themonitored inside air temperature; calculating a second average spacetemperature for a second time period based upon the monitored inside airtemperature; calculating a first average outdoor air temperature for thefirst time period based upon the monitored outdoor air temperature;calculating a second average outdoor air temperature for the second timeperiod based upon the monitored outdoor air temperature; and furthercontrolling the temperature control system based upon the supply airtemperature, the return air temperature, the monitored spacetemperature; the operating status of the ventilation system, thecalculated first average space temperature, the calculated secondaverage space temperature, the calculated first average outdoor airtemperature, and the calculated second average outdoor air temperature.22. The method of claim 21, wherein the temperature control systemfurther includes an outdoor air damper; and wherein the method furtherincludes: monitoring a mixed air temperature, wherein the mixed airtemperature is monitored within a housing of the temperature control,downstream of a return air supply and downstream of outside air;calculating an opening position of the outdoor air damper based upon themonitored return air temperature, the monitored mixed air temperature,and the monitored outdoor temperature; and further controlling thetemperature control system based upon the monitored opening position.23. The method of claim 22, wherein controlling the temperature controlsystem further includes: iteratively, at defined time periods, summing,for a first result, a product of the monitored operating status of theventilation system with a difference of the supply air temperature andthe monitored return air temperature and a difference of a product ofthe monitored operating status of the ventilation system and thecalculated opening position of the outdoor air damper with a differenceof the monitored outdoor temperature and the monitored return airtemperature; and further controlling the temperature control systembased upon the iteratively summing.
 24. The method of claim 23, whereincontrolling the temperature control system further includes:iteratively, at defined time periods, summing, for a second result, aproduct of the monitored operating status of the ventilation system andthe monitored opening position of the outdoor air damper with adifference of the monitored outdoor temperature and the monitored returnair temperature; and further controlling the temperature control systembased upon the iteratively summing.
 25. The method of claim 24, whereincontrolling the temperature control system further includes: furthercontrolling the temperature control system based upon a sum of the firstresult and the second result.
 26. The method of claim 23, whereincontrolling the temperature control system further includes: averaging adifference between the first average outdoor air temperature and thefirst average space temperature subtracted from a product of the sum ofthe first result and the second result and a variable M calculated by: adifference between the difference of the second average outdoor airtemperature for the second time period and the second average spacetemperature for the second time period and the difference between thefirst average outdoor air temperature for the first time period and thefirst average space temperature for the first time period divided by: adifference between the sum of the first result and the second resultcalculated at the second time period and the sum of the first result andthe second result calculated at the first time period.
 27. The method ofclaim 11, further comprising: monitoring a mixed air temperature,wherein the mixed air temperature is monitored within a housing of thetemperature control, downstream of a return air supply and downstream ofoutside air; calculating an opening position of the outdoor air damperbased upon the monitored return air temperature, the monitored mixed airtemperature, and the monitored outdoor temperature; further controllingthe temperature control system based upon the calculated damperposition.
 28. The method of claim 11, further comprising: estimatingheat energy produced inside the structure based upon the monitoredoutdoor air temperatures, the monitored indoor air temperatures, andoperating status of the temperature control system; and furthercontrolling the temperature control system based upon the estimated heatenergy produced.
 29. The method of claim 11, wherein the temperaturecontrol system includes one of a cooling subsystem, a ventilationsubsystem, and a heating subsystem.
 30. A method for operating atemperature control system having a plurality of temperature controlzones within a structure, the method comprising: monitoring outdoortemperature; monitoring an operating state of the temperature controlsystem; monitoring a supply air temperature and a return airtemperature; monitoring an operating status of a ventilation system;monitoring space temperature; monitoring a mixed air temperature,wherein the mixed air temperature is monitored within a housing of thetemperature control, downstream of a return air supply and downstream ofoutside air; calculating an opening position of the outdoor air damperbased upon the monitored return air temperature, the monitored mixed airtemperature, and the monitored outdoor temperature; calculating a firstaverage space temperature for a first time period based upon themonitored inside air temperature; calculating a second average spacetemperature for a second time period based upon the monitored inside airtemperature; calculating a first average outdoor air temperature for thefirst time period based upon the monitored outdoor air temperature;calculating a second average outdoor air temperature for the second timeperiod based upon the monitored outdoor air temperature; iteratively, atdefined time periods, summing, for a first result, a product of themonitored operating status of the ventilation system with a differenceof the supply air temperature and the monitored return air temperatureand a difference of a product of the monitored operating status of theventilation system and the calculated opening position of the outdoorair damper with a difference of the monitored outdoor temperature andthe monitored return air temperature; iteratively, at defined timeperiods, summing, for a result, a product of the monitored operatingstatus of the ventilation system and the monitored opening position ofthe outdoor air damper with a difference of the monitored outdoortemperature and the monitored return air temperature; predicting a spacetemperature and an outdoor air temperature for a subsequent time period;estimating an operating metric for temperature control system based uponthe (a) monitored interior temperature of the structure, (b) monitoredoutside air temperature, (c) monitored operating state of thetemperature control system, (d) predicted space temperature, and (e)predicted outdoor air temperature, (f) the result, (g) the calculatedopening position, (h) the supply air temperature, (i) the return airtemperature, (j) the monitored space temperature; (k) the operatingstatus of the ventilation system, (l) the calculated first average spacetemperature, (m) the calculated second average space temperature, (n)the calculated first average outdoor air temperature, and (o) thecalculated second average outdoor air temperature; and controlling thetemperature control system during the subsequent time period based uponthe estimated operating metric.